Fine-fuel furnace.



PATENTED MAR.' 20, 1906.v

PJN. SPEAR. FINE FUELPURNAGE. APrLIoATI'oN FILED SEPT. 12. 190;.

llllnnrlllnP-TILM when the said conduits are turned inward one toward the other and discharge into a shallow air-chamber e directly beneath the boilershell `and between' the latter and the said crown'or arch c2, said space being made tight along its sides and front, but preferably left open at its inner end toward the bridge-wall. The brick arch or crown c2 is provided throughout that area only which is subjected to the highest degree of heat from the products of combustion and preferably within the limits of the area of the shallow chamber e witha plurality of transverse air-supply openings e2, that lead from the said ehambere through the said arch or crown and communicate with the combustion-chamber below the crown, as best indicated in Fig. 1.

During the operation of the apparatus the draft created by combustionwithin the chamber and bythe passage of the products of combustion from the said combustion-chamber over the brid re-wall is sufficient to draw inward through t e conduits e e a current of air that becomes heated by radiation from the walls of the combustion-chamber as it flows through said conduits and is discharged into the chamber e', from which it is finally .destruction of the same. Admitting drawn throu h the perforatiens e2 into the combustion-c amber adjacent and in contact with the inner face of the crown or arch wall at that point only which is subjected to the highest degree of heat.. This air thus discharged adjaeent and in contact with the inner face of the arch or crown of the combustion-.chamber is there met by the outflowing products of combustion from the fuel and is cased to spread out somewhat in film form c lose agalnst the inner face of the crown or would melt, gutter, or otherwise damage the y said crown or arch.

Actual tests have shown thatv whatever be the exact action of' this air in repelling'or modifying the action of the products of combustion adjacent the crown or arch the melting or damaging of the arch by the products of combustion is entirelyeliminated, yet without. detracting materially from the de.- sired heat imparted to the arch from the )roducts of combustion. In other words, t 1e air thusadmitted having been heated during its passage thrdugh the conduits readily conflines with the products of combustion in the combustion-chamber and promotes combustion, and while it permits the arch -or crown of the furnace .to be suflciently heated for the best results, yetit prevents such injurious contact of the products of combustion with such crown or arch as would cause premature arch at that portion only subjected to the `eombustiori,

`thus effectually preventing destruction of the inner end of the arch, which ordinarily would become quickly destroyed under the action of the intense heat of the products of combustion owing in contact with it.Av F urther, to promote combustion within the combustionchamber I have provided a steampipe f, that leads from the steam-space ofthe boiler into and through the shallow air-chamber e', with its end preferably at the end of the arch c2. The end of this steami e is preferably provided with a number ofpiiii f', (see Fig. 3,) through which fine jets of steam are projected into-the upper part of the combustion-chamber and beyond the arch or crown, the steam bein stantially in the line of ow of the products of combustion toward and from the bridge-wall. I find that steam admitted at this olnt produces -better results than when a mitted in the ordinary manner. of the combustion-chamber serves not only to protect the steam-jet device from direct contact with the products of combustion and from consequent destruction thereby, but also acts as a su erheater to superheat the steam, and thereby increase its effective action in the combustion-chamber.

I have here described my invention in connection with one embodiment thereof; but it is to be understood that my invention is not limited to the embodiment or disclosure here made, but may be variously modified within the spirit and scope of the invention set forth.

' I claim- '1. A pulverulent-fuel-feedingfurnace, hoving a retort-like combustion-chamber, an arched crown extending part way through said chamber and provided with a plurality of transverse openin s at its-inner end only, an air-supply cham er located above said arched crown and communicatiiw with said openings, and a bridge-wall beyond the end of said arched crown for directing the products of combustion toward the inner end of said arched crown and causing a supply of air to be drawn through the transverse openingsin.

said crown into contact with the prorhu-.ts'ol whereby the crow'u is prdieuted at that oint only subjected to the highest degree ofheat of the products of eonibust ion.

2. A pulverulent-fuel-fecding furnace, having a retort-like combustion-chalnbcr, an

airat this arch or crown extending part way through point Iiind tends to promotecombustion as l said chamber, an air-supply chamber an'- thus projected sub- I 1e perforations The arch or crown c2 IOO IIO

. 815x562 t j 3 .rpnged above said arch or crown and in open communication with the combustion-chamber above the inner edge of said arch or crown,

a plurality of transverse openings insaid arch or lcrown at its inner end only andvcomrnunieating with said air-supplylchamber and'said combustion-chamber, and a bridge-*wall beyond the end of said archor crown for directing the products of combustion toward the inner end ofthe arch or crown and causing a supply of airto be drawn through the open end and said transverse openings ofthe arch or crown into contact with said products of combustion, whereby the inner 'edge and un- `der surface of the inner end onlyof the arch or crown is protected from the intense .heat of the products' of combustion. i

. 3. Apulverulent-fuelfeeding furnace,hav ing a retort-*like combustion-chamber, lan' arch or crown extending part waythrough said chamber, an ail -supply chamber arranged above said arch orvcrown and in opencozninunication with the combustionfcham i ,ber above the inner edge of said-arch or cr0wn,-

. drawn through the open end and said trans-y versc openings of the arch or crown .into conltact with said products of combustion, whereby the inner edge and under surface of theinner end yonly of the arch or crown'is pro-A I L/v tected from `tlef1ntense heat ofthe products of combustion. i 4; A pulverulent-fuel-feeding furnace having a retortlike combustionchamber, an arched crown extending art way throu h said chamber, means for delivering a supply of pulverulent-fuel particles'at the entrance end of said combusti on-char'nber and to cause their travel alon the same, a bridge-wall at therear ofsaid c amber to causethe upward y deflection of said fuel particles, means beyond 1 said bridgewall to cause said fuel particles to assume a substantially horizontal line oftravel, and means for supplying steam toV said combustion-chamber beyond said arch' toward said bridge-wall and in the'same en'- eral direction as the direction of trave of said fuel particles and products of combus tion. l V- 5. In a fuel-burnin apparatus the combinatio'n Withla pulveru ent-fuel-feeding device of a combustion-chamber having an arched crown extending part Way through said .chai-uber, a hot-air-su ply chamber above .said arched crown, a brid e-wall in said combustion -chamberbeyon Vsaid arch, and a steam-supply pipe leading through said airchambervfor' supplying heated air and steam to said combustion-chamber beyond said archy i .and in a direction toward said bridge-wall.

'f In testimony whereof I have signed my name to this specification in thepresen'ce of two 'subscribing Witnesses. t t

, T j FRANKl N. SPEAK Witnesses: l f

FREDERICK L. EMERrI 4A. ECHESLEY. 

